Removed inappropriate use of SerialTaskQueue from ClusterShapeLazyGetter #11562
Conversation
A SerialTaskQueue was added to ClusterShapeLazyGetter in an attempt to make it thread safe. Unfortunately, the implementation was safe since the internals of SiPixelClusterShapeCache could be changed while another thread was reading the data outside of the queue. In addition, performance measurements done using VTune showed the fequent calls to SerialTaskQueue were causing a heavy CPU load when run with 8 threads. The thread safety of SiPixelClusterShapeCache will have to be handled in a different way in the future once we start using more than one thread per Event.
|
A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_6_X. Removed inappropriate use of SerialTaskQueue from ClusterShapeLazyGetter It involves the following packages: RecoPixelVertexing/PixelLowPtUtilities @cmsbuild, @cvuosalo, @slava77 can you please review it and eventually sign? Thanks. |
|
please test |
|
The tests are being triggered in jenkins. |
|
@Dr15Jones: |
|
+1 Reversing an attempt to make SiPixelClusterShapeCacheProducer thread-safe, because the attempt didn't really work and had a performance cost. Some other approach will have to be used. There should be no change in monitored quantities. The code changes are satisfactory, and Jenkins tests against baseline CMSSW_7_6_X_2015-09-29-1100 show no significant differences, as expected. |
cmsbuild
added
reconstruction-approved
fully-signed
and removed
pending-signatures
reconstruction-pending
labels
|
This pull request is fully signed and it will be integrated in one of the next CMSSW_7_6_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar |
|
Missing not added |
|
+1 |
…erShapeLazyGetter Removed inappropriate use of SerialTaskQueue from ClusterShapeLazyGetter
A SerialTaskQueue was added to ClusterShapeLazyGetter in an attempt
to make it thread safe. Unfortunately, the implementation was not safe
since the internals of SiPixelClusterShapeCache could be changed
while another thread was reading the data outside of the queue.
In addition, performance measurements done using VTune showed
the fequent calls to SerialTaskQueue were causing a heavy CPU load
when run with 8 threads.
The thread safety of SiPixelClusterShapeCache will have to be handled
in a different way in the future once we start using more than one
thread per Event.